1. Field of the Invention
This invention relates generally to devices for filtering and separating fluids. More particularly, the present invention relates to fuel filters having a replaceable cartridge for removing foreign particles and separating water from the fuel supply system of an internal combustion engine.
2. Description of the Related Art
Diesel fuel supplies frequently contain significant quantities of abrasive particles and water which present the potential for permanent damage to the components of the fuel injection pump, the fuel delivery system and the engine. Consequently, an effective fuel filter as a practical necessity is conventionally incorporated into the fuel supply system of a diesel engine. A multitude of conventional fuel filters employ a disposable filter cartridge which is replaced at pre-established intervals of filter usage. Such fuel filters perform the dual function of removing particulate material from the diesel fuel and separating water from the fuel.
U.S. Pat. No. 4,976,852 and U.S. Pat. No. 5,084,170, which are assigned to the assignee of the present invention, disclose fuel filter assemblies to which the present invention relates. The fuel filters employ a base which mounts a disposable filter cartridge. In some disclosed embodiments, the cartridge includes a single stage filter system wherein fuel flows axially and radially to a filter element for removing particulate matter. The filter element also functions as a water barrier. Filtered fuel flows axially and exits through an outlet passage of the base. Water may be collected in a sump and periodically removed. The cartridge is secured to the base by a collar that engages a peripheral roll seam of the cartridge.
Most conventional fuel filter cartridges are permanently sealed metal canisters that contain a filter element and include grommets to seal the cartridge to the fuel inlet and outlet passages or ports. With use, the filter elements of such assemblies become clogged resulting in restricted fuel flow. The ability of the filter element to separate water also degrades over time. Accordingly, such cartridges must be replaced regularly to ensure the internal combustion engine is being supplied with an adequate flow of clean fuel.
Fuel filters have typically been constructed in the form of a metal can, permanently enclosing the filter element in a single use assembly. While these assemblies have proved to be effective and reliable, they are less than ideal in terms of waste of materials and disposal cost. Increased awareness of environmental protection and recycling of materials have led to a need for more efficient filtration systems having a minimum disposable component. In addition, environmental protection agencies seeking to reduce the volume of waste items associated with the automotive and trucking industries no longer allow used fuel filters into the normal waste stream, necessitating specialized and consequently more expensive disposal.
Briefly stated, the invention in a preferred form is a fuel filter cartridge assembly which includes a two-part housing containing a single use, incineratable filter unit. The housing is constructed of first and second cooperative sections, detachably connected to allow replacement of the used filter unit. The filter unit is constructed of a continuous, fan shaped, pleated filter element, typically composed of a form of paper. Axially spaced first and second end caps, constructed of incineratable plastic, provide support structure for the filter element and also provide a platform for the attachment of grommets which seal the unit to the fuel inlet/outlet conduit.
The can-shaped housing first section defines a central axial opening for receiving a typically coaxial fuel inlet/outlet conduit projecting from a cartridge-receiving base module. A sealing grommet is affixed to the inner edge of the opening for fluidly sealing the housing to the received conduit. The interior surface of the housing first section preferably incorporates at least one groove which is cooperative with tabs formed on the first end cap of the filter unit. The cooperative groove and tab structures function as a key system to prevent the use of incompatible filter elements in a particular housing.
The filter unit interacts with the housing grommet in a novel manner. The housing grommet has a quasi-tubular structure that extends into the housing a short axial distance and terminates at a second end. In a preferred embodiment, the housing grommet second end has at least one radially extending protrusion which functions as a locator and a retainer ring to ensure proper axial positioning and sealing of the filter unit within the housing.
The housing grommet is configured to cooperate with a complementary structure located in the filter element first end cap. The central opening in the first end cap is defined by an inwardly projecting shoulder having an interior diameter less that the external diameter of the grommet protrusion. The shoulder is located axially so that when the filter element is installed within the housing, this shoulder rides over the protrusion and exerts a radially inward force on an axially intermediate area of the sealing grommet, forcing the grommet into sealing contact with the exterior surface of the fuel conduit.
An ecological fuel filter element according to the present invention provides a filter element which lessens the potential impact of fuel filter replacement on the environment by removing fuel and solid waste from the waste stream. A filter element constructed according to the claimed invention will contain no metal and will be composed of incineratable materials.
The claimed invention removes the filter cartridge housing from the waste stream by making it possible to open the housing and replace only the used filter element. Fuel inside the housing can be collected and re-cycled immediately. The filter element and its trapped particulates can then be destroyed efficiently by incineration. Using this technique will ease compliance with increasingly strict environmental protection requirements while greatly reducing disposal costs.
An object of the invention is to provide a new and improved fuel filter cartridge and element which enable the cost effective disposal of the spent element in an efficient, environmentally friendly process.
Another object of the invention is to provide a new and improved fuel filter cartridge assembly of efficient and low cost construction which reduces waste and controls the release of fuel contaminants into the environment.
A further object of the invention is to provide a new and improved disposable fuel filter element which can be efficiently installed and replaced and functions to enhance the sealing integrity of the filter assembly.
A yet further object of the invention is to provide a new and improved fuel filter element which can be disposed of in a cost-effective manner which is compliant with strict environmental regulations.
Other objects and advantages of the invention will become apparent from the drawings and the specification.